I just finished the first version of EPUBReader which supports Firefox Mobile on the N900/N810 and searching for people who would like to test it.
EPUBReader is a free Firefox add-on which lets you read ePub-files directly in Firefox. You find here more information http://www.epubread.com/mobile/.
EPUBReader for PC exists already for a while, new is the mobile version for the N900/N810. So I would be very happy if you try it and give me feedback .
Here are the details for the installation:
Firefox Mobile 1.0 needs to be installed first. You can install it from here.
is it possible to make the add-on available for the built-in browser?
Okay, I found this information about MicroB:
"In place of Mozilla's XUL-based user interface, MicroB uses the Maemo-native (GTK-based) Hildon API and widgets."
So unfortunately EPUBReader doesn't work with MicroB because it makes heavy use of XUL for the frontend. AdBlock doesn't have a frontend itself, that's the reason why it works with MircoB.